Electric furnace for melting and liquefying ferro-alloys.



. W. SGHEMMANN 55 J. BRONN.

ELECTRIC. FURNACE FOR MELTING AND LIQUEFYING PERRO ALLOYS.-

APILIOATION FILED DEO.14, 1910.

' 1,056,456. Patented Mar. 18, 1913.

W l4; 1 a4 9% UNITED STATES T GFFICE;

WILHELM SCHEMMANN AND JEGOR BRONN, OF ROMBACH, GERMANY, ASSIGNORS TO ROMBACHER I-IllTTENWERKE, OF ROMBACH, GERMANY, Q ORPORATION OF GER- MANY.

ELECTRIC FURNACE FOR MELTING AND LIQUEFYING FERRO-ALLOYS.

Specification of Letters Patent.

Fatented Mar. 18, 1913.

To all whom it may concern:

Be it known that we, VV-I HELM SCHEM- MANN, a citizen of the German Empire, and Jason BRONN, a subjectof the Czar of Russia, residing at Rombach, in the Empire of Germany, have invented certain new and useful Improvements in Electric Furnaces for Melting and Liquefying Ferro-Allovs, of which the following is a specification.

The advantages of an addition of ferromanganese in liquid form to the ingot-iron or mild steel to be deoxidized, have been pointed out heretofore by us in United States Letters Patent No. 915,488 obtained by us, and we have recommended for this purpose the employment of an electric fur.- nace with pure resistance heating- It has been found, however, by continuous practical working of these furnaces that although metal could be easily melted in the troughfurnaces therein suggested, that gradually a great deal of slag was collected in the melting trough which slag remained tough and had to be removed from time to time by means of tools, which caused frequent interruptions in the working of the furnaces and by which the troughs were liable to be sub jected to damage. When, however, it is attempted to melt fcrro-manganese in an electric arc-furnace such as is generally used for refining steel, a thick brown smoke begins at once to escape from the furnace owing to thecombustion and evaporation of the manganese, and the loss of manganese which takes place is so great that the re-melting of,- f erro-manganese becomes unprofitable.

It is well known that in electric arc-furnaees which are used in the refining of steel, the drop of the tensionwithin the electric are, that is to say, when measured between the carbon-block and the metal bath, amounts to from 4:54 5 volts. It has been found however that, when thecarbon electrode is lowered to such an extent that it just touches the surface of the bath, and that when such a tension of the current is used, that the difference or drop of tension between the carbon and the metal bath amounts to only from 1648 vblts, and that this drop is below the electromotive counter-force of the are, which is generally taken to be about 30 volts, it is possible to obtain, by the contact-resistance thus produced, an amply suflicient beating of the melting bath without any noticeable loss of manganese taking place.

In the accompanying drawings, Figures 1 and 2 represent respectively a vertical longitudinal and a vertical transverse section of our improved electric furnace with three hanging electrodesfor melting ferr0-manganese and similar alloys, Figs. 3 and 4 represent respectively a horizontal section and a verticalilongitudinalsection of a modified two-trough combined electric furnace, Fig. 5, a horizontal section of a single trough combined electric furnace adapted to be operated by a single-phase current, the'vertical' section of which is represented in vFig. 4, and Figs. 6 and 7 are respectively a vertical longitudinal and a horizontal section of a single trough or hearth electric furnace with a hanging and an inclosed electrode showing our invention.

Similar letters of reference indicate corresponding parts throughout the several figures.

A furnace intended for multiphase current, is illustrated in Figs. 1 and 2. It wills be seen, that its construction is similar to that generally used for steel-furnaces, and that like the latter, it can also be Worked with an ordinary alternating current, that is to say, with only two electrodes. It is, however, as already stated, an essential condition that for obtaining the desired degree of heat by contact-resistance instead of archeating, the drop or diti'erence of tension between the electrode and the molten bath should not exceed the limits above stated.

The new observation that by contact-rcsistance, sutiicient heat is obtained for ren'ielting and keeping liquid ferro-manganese and the slag which forms on the same, in duced the applicants to change the pure resistancefurnaces described intheir U. S. Patent No. 915,485 to a combined system in which resistance-heating is-combined with heating by an electric arc of low tension, or which is the same by means of contact-resistance, so that the metal-bath forlns'lhe heat-resistance"in trough-furnace in the well known manner, while the heating of the slag-covering is produced by the heat of an electric arc of low tension that is by contactresistance. Such a combined furnace which can be worked with a lllllltlphuSCCllIl'QIlll, is

'5 them in liquid state, which comprises and means for pressing the metallic body I said bodies, and means for pressing the into contact with the carbon-plates. metallic bodies into contact with the carbon 15 4. An electric furnace for melting ferroplates for reducing the frequent disconnecmanganese and similar alloys and keeping tion and connection of the current-conductors.

troughs for the metal bath united at oneend I In testimony, that We claim the foregoing so as to fornr a heartln an electrode snsas our invention, We have signed our names 20 pended above the hearth and in contact I in presence of two subscribing Witnesses. With the bath, carbon-blocks submerged in VVILHELM SCHEMMANN.

10 the opposite ends of the troughs, inter-i JEGOR BRONN.

changeable carbon-plates above said blocks, I Witnesses: metallic current-conchicting bodies above the i LoUls VANDORY, plates, current-conductors connected with JOSEPH S'roDTEN.

v M fioples of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

